Fungal infections in cancer patients are difficult to diagnose and such diagnoses are frequently only made at necropsy. Earlier, aggressive diagnostic procedures (see #06913 regarding bronchial brushing) have improved the diagnostic accuracy and earlier therapy has become possible. Evaluation of epidemiologic factors has also identified the at risk population: of 125 patients with acute leukemia, 18 cases had invasive aspergillosis and 11 of the 18 had nose cultures growing Aspergillus. Ten of these 11 had documented invasive disease. Of 125 patients, 61 had sterile nose cultures and 14 of 18 cases had such sterile nose cultures. Thus patients with positive nose cultures may have invasive disease and patients with sterile nose cultures are at risk for developing it. With the evaluation of earlier diagnostic tests for the establishment of systemic mycoses, we are evaluating the addition of rifampin to amphotericin-B to evaluate the known in vitro synergistic effect against many fungi. This treatment is used for suspected and documented fungal infections. Forty-one patients have been randomly allocated to date, but after stratification for the various fungal infections, there are too few patients from which to draw meaningful conclusions other than that early application of therapy continues to be the best approach to infection resolution.